Deficiency of estrogens during menopause can lead to a number of complications including hot flushes, reduced bone density, mood swings, vaginal atrophy, etc. These symptoms are commonly treated with synthetic hormones. Although postmenopausal symptoms can be alleviated, hormone replacement therapy (HRT) was discovered to be associated with increased cardiovascular disorders in one of the largest studies of its kind (Women's health Initiative, WHI) (Seelig, Altura et al. 2004). HRT was also linked to increased risk of breast and ovarian cancer (Fernandez, Gallus et al. 2003, Gambacciani, Monteleone et al. 2003). After the WHI trial results were published, the use of HRT was reduced dramatically. Many postmenopausal women have resorted to alternative therapy because phytoestrogens are generally considered to be safe and efficacious. The use of soy and Red clover; the most common species used is Trifolium pratense, which are rich in phytoestrogens, has been on the rise (Beck, Rohr et al. 2005). Despite the trend, clinical trial results on phytoestrogens, however, have been equivocal. For example, the effects of Red clover on postmenopausal bone loss have been marginal (Beck, Rohr et al. 2005, Booth, Piersen et al. 2006, Wuttke, Jarry et al. 2007, Ma, Qin et al. 2008, Lagari and Levis 2014). Despite occasional success, a large percentage of clinical trials showed no significant effects on postmenopausal bone loss. Similar data have been obtained for other postmenopausal symptoms such as hot flashes (Ghazanfarpour, Sadeghi et al. 2015, Ghazanfarpour, Sadeghi et al. 2016) and vaginal atrophy (Ghazanfarpour, Latifnejad Roudsari et al. 2015, Ghazanfarpour, Sadeghi et al. 2016). Alternative therapy has not replaced HRT effectively. A recent study showed that the trend of women moving away from HRT has led to an alarming increase in bone fractures and it is estimated that fractures related to menopause is expected to exceed 40,000 per year in women aged 65-69 years (Gambacciani, Ciaponi et al. 2007). Since the side effects of HRT were publicized after the WHI trial, it has since been reevaluated. There is no consensus with regard to HRT's safety among the medical research community. Therefore, a much closer look at the ‘less than expected’ effects of phytoestrogens should be undertaken because the toxicity profile of this type of products is so much more favorable.
Besides HRT, there are no drugs that could be used effectively for treating climacteric symptoms such as hot flashes and vaginal atrophy. Anti-depressants like Prozac, Paxil or Effexor, blood pressure medications like clonidine, anti-seizure drugs like gabapentin, and a paroxetine formula Brisdelle have been used for treating hot flashes. However, these drugs produce significant side effects, and the efficacy is at best marginal. Ospemifene, a selective estrogen receptor modulator, has been approved for the treatment of vaginal atrophy. However, its long term safety has not been ascertained. Genistein, a soy isoflavone has been shown to have some positive effects on vaginal cell structure.
The major bioactive isoflavones in soy are genistein, daidzein, glycitein and prunetin (Setchell and Cassidy 1999). They are also present in their glycoside forms. There are three classes of bioactives in red clover: isoflavones, coumestrols and lignans (Beck, Rohr et al. 2005). The quantity of coumestrols and lignans is small; therefore, their contribution to the overall activity is likely minimal. The major isoflavones in red clover are Biochanin A and formononetin (Liu, Burdette et al. 2001, Overk, Yao et al. 2005, Booth, Overk et al. 2006). Genistein and daidzein are present in minute quantities. Biochanin A and formononetin are precursors of their respective active moieties, genistein and daidzein. The conversion takes place in the intestine by intestinal flora and liver, although the relative significance has not been established. Daidzein is converted by bacteria in the colon to form a more estrogenic metabolite, equol. In Red clover, a significant quantity of Biochanin A and formononetin is in the form of glycosides. The glycosides in soy and red clover are converted to their respective aglycones by the intestinal flora before absorption (Setchell and Cassidy 1999).
Relative absorption of isoflavone glycoside and their respective aglycones is a subject of controversy. Although the cause of controversy is not readily apparent, the low solubility of the aglycones in a preparation may have a profound effect on their dissolution, metabolism and absorption.
Formononetin and Biochanin A are de-methylated by the intestinal micro flora to produce two active metabolites daidzein and genistein, respectively (Hur and Rafii 2000). However, the site of this metabolic pathway is questioned (Tolleson, Doerge et al. 2002).
Metabolism of isoflavones is mainly mediated by Phase II enzymes in the enterocytes and hepatocytes. Although metabolism of individual isoflavones in rats has been well characterized (Jia, Chen et al. 2004, Chen, Lin et al. 2005, Chen, Wang et al. 2005), interaction between components has not been evaluated.
Clinical studies showed that extracts of red clover or soy are safe; however, their efficacies are equivocal (Booth, Piersen et al. 2006, Lagari and Levis 2014). Although there are proprietary products in the market, which have shown potentials for treating or preventing postmenopausal osteoporosis, hot flushes and vaginal atrophy; these products unfortunately, do not have the quality of a drug. The major shortcomings for the design of these products in the market are that they have not taken into consideration of the interplay between pharmacokinetics and pharmacodynamics. In other words, proper dosage and/or dosing interval are empirically decided.
In this invention, the interplay between these “active” components is evaluated and quantified using a proprietary physiologically based pharmacokinetic and pharmacodynamic model (PBPKPD).
One of the objectives of the present invention is to provide compositions comprising active ingredients of Red clover that are effective in modulating, preventing or treating climacteric symptoms. The compositions provided herein are formulated as special dosage forms and require a much lower dosage of phytoestrogens than Red clover products available in the market. The advantage of the present compositions is their consistency. By modifying the mode of delivery, the other advantage of the present compositions is the increase in the bioavailability of the aglycones and eliminates the conversion to their respective bioactive metabolites in the colon, which leads to variability in efficacy.